求不定积分∫dx/(e^x+1)

来源:学生作业帮助网 编辑:六六作业网 时间:2024/11/22 06:08:46
求不定积分∫dx/(e^x+1)求不定积分∫dx/(e^x+1)求不定积分∫dx/(e^x+1)∫dx/(e^x+1)=∫(1+e^x-e^x)dx/(e^x+1)=∫dx-∫e^xdx/(e^x+1

求不定积分∫dx/(e^x+1)
求不定积分∫dx/(e^x+1)

求不定积分∫dx/(e^x+1)
∫dx/(e^x+1)
=∫(1+e^x-e^x)dx/(e^x+1)
=∫dx-∫e^xdx/(e^x+1)
=x-∫d(e^x+1)/(e^x+1)
=x-ln(e^x+1)+C

令e^x=t,则x=lnt,dx=dt/t
∫dx/(e^x+1) =∫dt/(1+t)t=∫(1/t-1/(1+t))dt=∫dt/t-∫dt/(1+t)=lnt-ln(1+t)+C=ln(t/(t+1))+C=ln(e^x/(e^x+1))+C